1. Field of the Invention
The invention relates to an electrically connectable module in which an electrical connector is embedded in a substrate of an electrically insulating polymer matrix doped with an electrically insulating fibrous filler capable of heat conversion to an electrically conductive fibrous filler. Localized heating of the substrate adjacent the electrical connector produces a conductive trace formed in the substrate and forms an electrical connection between the pre-embedded electrical connector and the conductive trace. More particularly, the invention relates to an electrically connectable module in which an electrical connection is formed between one end of an electrical connector (previously embedded in a polymer matrix) and a laser-produced conductive trace formed in the polymeric substrate, for the dual purposes of using the electrical connector for electrodepositing a conductive material onto the conductive trace and for subsequent electrical connection to an external electrical component.
2. Discussion of Related Art
In electrical machines such as image reproducing devices, it is necessary to distribute power and/or logic signals to various sites within the machine. Traditionally, this has taken the form of using conventional wires and wiring harnesses in the machine to distribute the power and logic signals to the various functional elements in the machine.
As an alternative to wires, it is known to use a CO.sub.2 laser to burn conductive traces in a polymeric material that has been doped with carbon fibers so that the untreated material (not subjected to the laser) is not conductive. When locally heated by the laser, the polymeric material volatilizes to leave a conductive network of polymer residue and conductive dopant. U.S. Pat. No. 4,841,099 teaches how an electrically insulating polymer matrix is filled with an electrically insulating fibrous filler capable of heat conversion to an electrically conducting fibrous filler, to form a continuous electrically conductive path by the in-situ heat conversion of the electrically insulating fibrous filler using a laser. The entire disclosure of U.S. Pat. No. 4,841,099 is herein incorporated by reference.
In order to make the conductivity of the traces more sufficient for many applications, it has been proposed that metal be electrodeposited onto the traces. One advantage of this electrodepositing approach is to place metal conductors onto the polymeric material in the trough or channel created by the laser with the metal adhering to the polymeric material. However, the prior art has not developed or suggested methods for reliably electroplating the trace, or for connecting the traces to electrical connectors in the polymeric material for distributing power or signals between the trace and an external component.
U.S. Pat. No. 4,604,678 to Hagner discloses a circuit board plated with high density electrical traces connected to respective terminals of a number of electrical current components mounted on a substrate. Grooves on the substrate can be machined by a laser. The components are assembled before the grooves are plated to minimize production costs and assure electrical connection between the plated laser-formed grooves and the terminals of respective components. The conductive traces overlie and are in electrical contact with chip pads.
U.S. Pat. No. 3,984,620 to Robillard et al. discloses an integrated circuit chip test and assembly package having a semiconductor interconnection substrate with apertures for integrated circuits. The assembly package includes an interconnection with external leads which are located between insulating layers of the substrate.
U.S. Pat. No. 3,818,279 to Seeger, Jr. et al. discloses an electrical interconnection and contacting system comprising a flexible plastic insulator, most preferably an elastomeric substrate having at least one layer of electrically conductive elastomeric material embedded therein. The system is useful in coupling integrated circuits to other circuitry.